Institute for Integrative Nanosciences, Leibniz IFW Dresden, Helmholtzstraße 20, 01069 Dresden, Germany.
Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstraße 2, 30167 Hannover, Germany.
Phys Rev Lett. 2019 Oct 18;123(16):160502. doi: 10.1103/PhysRevLett.123.160502.
Transferring entangled states between photon pairs is essential in quantum communication. Semiconductor quantum dots are the leading candidate for generating polarization-entangled photons deterministically. Here we show for the first time swapping of entangled states between two pairs of photons emitted by a single dot. A joint Bell measurement heralds the successful generation of the Bell state Ψ^{+}, yielding a fidelity of 0.81±0.04 and violating the CHSH and Bell inequalities. Our photon source matches atomic quantum memory frequencies, facilitating implementation of hybrid quantum repeaters.
在量子通信中，光子对之间的纠缠态转移至关重要。半导体量子点是确定性地产生偏振纠缠光子的首选。在这里，我们首次展示了单个点发射的两对光子之间纠缠态的交换。联合贝尔测量预示着成功产生贝尔态 Ψ^{+}，保真度为 0.81±0.04，并违反了 CHSH 和贝尔不等式。我们的光子源与原子量子存储频率匹配，有利于混合量子中继器的实现。
